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CHEMISTRY MCQS
Can someone explain these?
Q4.o/n/10_11 . Sulfur dioxide, SO2, is added to wines to prevent oxidation of ethanol by air. To determine the
amount of SO2, a sample of wine is titrated with iodine, I 2. In this reaction, one mole of SO2 is
oxidised by one mole of I 2.
What is the change in oxidation number of sulfur in this reaction?
A +2 to +4 B +2 to +6 C +4 to +5 D +4 to +6
Q21.m/j/10_11 When heated with chlorine, the hydrocarbon 2,2-dimethylbutane undergoes free radical substitution.
In a propagation step the free radical X•
is formed.
When heated with chlorine, the hydrocarbon 2,2-dimethylbutane undergoes free radical
substitution.
In a propagation step the free radical X•
is formed.
(I dont know how to insert an image so iv given the question no and the year)
How many different forms of X•
are possible?
A 1 B 2 C 3 D 4
Q 32 S10_11 Which reactions are redox reactions?
1 CaBr2 + 2H2SO4 → CaSO4 + Br2 + SO2 + 2H2O
2 CaBr2 + 2H3PO4 → Ca(H2PO4)2 + 2HBr
3 CaBr2 + 2AgNO3 → Ca(NO3)2 + 2AgBr
Q9 w10_11 In a calorimetric experiment 1.60 g of a fuel is burnt. 45 % of the energy released is absorbed by
200 g of water whose temperature rises from 18 ° C to 66 °C. The specific heat capacity of water is
4.2 J g–1K–1
.
What is the total energy released per gram of fuel burnt?
A 25 200 J B 56 000 J C 89 600 J D 143 360 J
Q22 w10_11 A compound Y has all of the properties below.
• It is a liquid at 25 °C.
• It mixes completely with water.
• It reacts with aqueous sodium hydroxide.
What could Y be?
A ethanoic acid
B ethanol
C ethene
D ethyl ethanoate
Q 35 w10_11 Disproportionation is the term used to describe a reaction in which a reactant is simultaneously
both oxidised and reduced.
To which incomplete equations does the term disproportionation apply?
1 Cl2(g) + 2OH–
(aq) → H2O(l) + Cl –
(aq) + ……
2 3Cl 2(g) + 6OH–
(aq) → 3H2O(l) + ClO3
–
(aq) + ……
3 2NO2(g) + H2O(l) → HNO3(aq) + ……
Can someone explain these?
Q4.o/n/10_11 . Sulfur dioxide, SO2, is added to wines to prevent oxidation of ethanol by air. To determine the
amount of SO2, a sample of wine is titrated with iodine, I 2. In this reaction, one mole of SO2 is
oxidised by one mole of I 2.
What is the change in oxidation number of sulfur in this reaction?
A +2 to +4 B +2 to +6 C +4 to +5 D +4 to +6
Q21.m/j/10_11 When heated with chlorine, the hydrocarbon 2,2-dimethylbutane undergoes free radical substitution.
In a propagation step the free radical X•
is formed.
When heated with chlorine, the hydrocarbon 2,2-dimethylbutane undergoes free radical
substitution.
In a propagation step the free radical X•
is formed.
(I dont know how to insert an image so iv given the question no and the year)
How many different forms of X•
are possible?
A 1 B 2 C 3 D 4
Q 32 S10_11 Which reactions are redox reactions?
1 CaBr2 + 2H2SO4 → CaSO4 + Br2 + SO2 + 2H2O
2 CaBr2 + 2H3PO4 → Ca(H2PO4)2 + 2HBr
3 CaBr2 + 2AgNO3 → Ca(NO3)2 + 2AgBr
Q9 w10_11 In a calorimetric experiment 1.60 g of a fuel is burnt. 45 % of the energy released is absorbed by
200 g of water whose temperature rises from 18 ° C to 66 °C. The specific heat capacity of water is
4.2 J g–1K–1
.
What is the total energy released per gram of fuel burnt?
A 25 200 J B 56 000 J C 89 600 J D 143 360 J
Q22 w10_11 A compound Y has all of the properties below.
• It is a liquid at 25 °C.
• It mixes completely with water.
• It reacts with aqueous sodium hydroxide.
What could Y be?
A ethanoic acid
B ethanol
C ethene
D ethyl ethanoate
Q 35 w10_11 Disproportionation is the term used to describe a reaction in which a reactant is simultaneously
both oxidised and reduced.
To which incomplete equations does the term disproportionation apply?
1 Cl2(g) + 2OH–
(aq) → H2O(l) + Cl –
(aq) + ……
2 3Cl 2(g) + 6OH–
(aq) → 3H2O(l) + ClO3
–
(aq) + ……
3 2NO2(g) + H2O(l) → HNO3(aq) + ……
